The southpaw cleared waivers, and he then posted a 3.27 ERA, 1.29 WHIP and .249 batting average against in 38 outings (63 1/3 innings) between Double-A Portland (51 1/3 innings) and Triple-A Pawtucket (12 innings) during 2017.

Left-handed hitters batted .206 against him at Portland and .071 against him at Pawtucket.

Back again on the 40-man here in 2018, Jerez will enter spring training Feb. 14 competing for the secondary left-handed reliever role on the Opening Day 25-man roster. The organization lacks left-handed relief depth. Jerez has a big opportunity ahead of him.

"I mean, there wasn't disappointment (last offseason) because I understand. I understand that I had a bad year," Jerez said. "I understand they made that decision. But as soon as I knew that, I decided to push more to demonstrate to them that I can do it. This is the game I want to play. That's the reason I pushed more. ... That way, they can trust me."

Overcoming challenges is nothing new to Jerez. The Red Sox drafted him as an outfielder in the second round (81st overall) in 2011.

Jerez posted a disappointing 4.71 ERA and 1.54 WHIP in 40 games (65 innings) for Portland during 2016.

"From 2016 to 2017 there was a big difference with me," Jerez said. "2016, I know I had a bad year. When things happened, I learned from that. I told myself I've got to push myself more. I've got to be more mature, more open with my mind to learn good things that's going to help like in 2016. I was working a lot after the season. I was working more on my command. I was working, trying to get more velo. And I saw the results after that."

Jerez also made changes to his repertoire.

"I was using the changeup in 2016, and I deleted that for the splitter," he said. "It works a lot for me. I get a lot of good results with the splitter."

Being added to the 40-man this past November motivated him just like being subtracted from it a year ago.

"Those are good moments and push you to work more," Jerez said. "Those good things push you to work more because you want to get to the point where you want to be."

That point is the majors, obviously.

This spring marks Jerez's second major league spring training camp. He spent 2016 at big league camp, then spent last year at minor league camp.

There's certainly a chance for him to make the team out of camp this spring unlike in 2016 when he had less experience.

"I don't think it's going to be nothing different (from 2016)," he said. "Just like I said, you've got to work hard, push yourself and do your job. When the time comes, you've got to do your job. So that way, we're going to have better results. So at end, they're going to make the decision."

Jerez pitched in winter ball this offseason. He posted a 3.18 ERA (2 earned runs, 5 2/3 innings), 1.06 WHIP and .167 batting average against in the Dominican League.

"Really good experience," he said. "There's a lot of big (players) at different levels. There's big league guys. Guys that go to Japan to play. And it was a good experience for me."